Interferon treatment inhibits glycosylation of a viral protein

Earlier, we reported a 30-200-fold reduction in the yield of infectious vesicular stomatitis virus (VSV) released from L cells treated with 10-30 reference units ml-1 of interferon (IFN); however, in these cultures virus particle production, as measured by VSV particle-associated viral RNA, virus nucleocapsid protein and viral transcriptase, was inhibited less than 10-fold. There was biochemical and morphological evidence of a significant reduction in glycoprotein (G) and membrane protein (M) of VSV particles released from IFN-treated cells. We compare here the effects of tunicamycin (TM) and IFN in L cells. Treatment with TM or IFN reduced the production of infectious VSV particles, decreased the amount of G and M proteins in VSV released from treated cells, and inhibited an early step in the formation of asparagine-linked oligosaccharide chains, the incorporation by membrane preparations from treated cells of N-acetylglucosamine into glycolipids with the properties of dolichol derivatives.